Monday, January 7, 2013

Signature Electronic Signs - convert to Arduino

I have removed three of the Cadaces modules and have written some new code to make them work. Next is to hard wire the interface circuitry instead of using jumper wires.

Once the controller is wired up and the sign is put back together here is what it looks like. The picture does not tell the whole story, the display blinks, and the more lines that are enabled the more it blinks. I will have to work on improving the software to fix that problem.

Here is the new Arduino controller on the left compared to the old sign controller on the right:

Here is the Arduino Controller installed into the Signature Electronic Sign. I goofed a little bit in the layout so that the ribbon cables must be flipped around backwards so that the stripe is to the right.

Here is the schematic diagram. I wired it with point to point wiring, however a circuit board or wire wrap would have been easier to do.

Last of all here is the code for the sign. It was written without scrolling and set up for up to four lines of text. It still needs some work, like the ability to convert a line of text into an array of characters automatically. I did that manually.

4 comments:

If you write an MHVLib driver that extends Display_Monochrome_Buffered, then you will get text rendering, scrolling, animation, etc for free.

http://www.makehackvoid.com/project/MHVLib

Your class should implement an flush() method, which would write the contents of the framebuffer to the display. This would then be called manually when the framebuffer is ready to display the updated content.

Once this is done, you can call any methods made available from Device_TX on the display, such as write(), write_P(), printf(), etc, and subsequently call txAnimation() to scroll the text.

For the user-side, you can check out mhvlib-tutorial-HT1632, which is a smart LED matrix (maintains it's own buffer), and exposes the same user-facing interface.

I have a 70×14 led display that’s original amplifier and controller are missing. If you want it you can have it. It uses 18 TPIC6B595 Texas Instrument chips. You will need to build a 7 or 14 channel amplifier circuit card and a arduino.Dave G